Events are published by Concentratord and can be received by creating a
ZeroMQ SUB socket. The first frame
holds the event type (string), the second frame holds the event payload encoded
api/proto/gw/gw.proto in chirpstack
for the Protobuf message definitions).
Uplink received by the gateway (
UplinkFrame Protobuf message).
Gateway statistics (
GatewayStats Protobuf message).